Evening chronotype is associated with changes in eating behavior, more sleep apnea, and increased stress hormones in short sleeping obese individuals

The association of self-reported sleep and circadian measures with glycemic control and diabetes complications among young adults with type 2 diabetes

We aim to examine the association of sleep duration, sleep quality, late chronotype, and circadian misalignment with glycemic control and risk of complications in young adults with youth-onset type 2 diabetes followed in the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study. Self-reported sleep duration, quality, timing, and circadian misalignment were assessed via a modified Pittsburgh Sleep Quality Index (PSQI) questionnaire, and chronotype was assessed via the Morningness-Eveningness Questionnaire (MEQ). We examined diabetes complications including loss of glycemic control (defined as hemoglobin A1c ≥8%), hypertension, dyslipidemia, albuminuria, and diabetic peripheral neuropathy. Multivariable logistic regression models were constructed to assess associations between sleep and circadian measures with outcomes of interest, such as loss of glycemic control and diabetes complications. A total of 421 participants (34.2% male), mean age 23.6 ± 2.5 yr, mean body mass index (BMI) of 36.1 ± 8.3 kg/m2, and mean diabetes duration of 10.0 ± 1.5 yr were evaluated. Self-reported short sleep duration, daytime sleepiness, and sleep quality were not associated with loss of glycemic control or diabetes complications. Late self-reported bedtime (after midnight) on work/school nights, rather than self-expressed chronotype or circadian misalignment, was independently associated with loss of glycemic control. An association was seen between late bedtimes and albuminuria but was attenuated after adjusting for depression. In conclusion, late bedtime on work/school days, rather than short sleep duration, daytime sleepiness, or poor sleep quality, was independently associated with loss of glycemic control in this longitudinal cohort of young adults with youth-onset type 2 diabetes.NEW & NOTEWORTHY The prevalence of type 2 diabetes in youth is increasing at an alarming rate. Identifying potentially modifiable factors modulating glycemic control is critically important to reduce micro and macrovascular complications. In a large cohort of youth-onset type 2 diabetes, self-reported late bedtime on work/school days was independently associated with loss of glycemic control in this longitudinal cohort of young adults with youth-onset type 2 diabetes.

Association of Sleep Pattern and Genetic Susceptibility with Obstructive Sleep Apnea: A Prospective Analysis of the UK Biobank

Purpose

The prevalence of obstructive sleep apnea (OSA) is high worldwide. This study aimed to quantify the relationship between the incidence of OSA and sleep patterns and genetic susceptibility.

Methods

A total of 355,133 white British participants enrolled in the UK Biobank between 2006 and 2010 with follow-up data until September 2021 were recruited. We evaluated sleep patterns using a customized sleep scoring method based on the low-risk sleep phenotype, defined as follows: morning chronotype, 7-8 hours of sleep per day, never/rarely experience insomnia, no snoring, no frequent daytime sleepiness, never/rarely nap, and easily getting up early. The polygenic risk score was calculated to assess genetic susceptibility to OSA. Cox proportional hazard models were used to evaluate the associations between OSA and sleep patterns and genetic susceptibility.

Results

During a mean follow-up of 12.57 years, 4618 participants were diagnosed with OSA (age: 56.83 ± 7.69 years, women: 31.3%). Compared with those with a poor sleep pattern, participants with a normal (HR: 0.42, 95% CI: 0.38-0.46), ideal (HR: 0.21, 95% CI: 0.19-0.24), or optimal (HR: 0.15, 95% CI: 0.12-0.18) sleep pattern were significantly more likely to have OSA. The genetic susceptibility of 173,239 participants was calculated, and the results showed that poor (HR: 3.67, 95% CI: 2.95-4.57) and normal (HR: 1.89, 95% CI: 1.66-2.16) sleep patterns with high genetic susceptibility can increase the risk for OSA.

Conclusion

This large-scale prospective study provides evidence suggesting that sleep patterns across seven low-risk sleep phenotypes may protect against OSA in individuals with varying degrees of genetic susceptibility.

Psychometric properties of the Turkish reduced morningness and eveningness questionnaire

The aim of this study was to examine the psychometric properties of the 5-item Turkish Reduced Morningness-Eveningness Questionnaire (rMEQ) for the first time. The study involved 875 university students in an adaptation and validation study. Participants completed the rMEQ, MEQ, Depression Anxiety Stress Scale-21 (DASS-21), Insomnia Severity Index (ISI), Barratt Impulsiveness Scale Short Form (BIS-SF), and Oxford Happiness Questionnaire Short Form (OHQ-SF). The factor structure, convergent validity, internal consistency, sensitivity, and specificity of the rMEQ were examined. The confirmatory factor analysis showed that the rMEQ had a one-dimensional structure with good fit indices (χ2/df = 2.94, CFI = 0.990, TLI = 0.979, RMSEA = 0.047, and SRMR = 0.019). There was a significantly strong correlation between rMEQ and MEQ. In addition, we found a significantly weak correlation between rMEQ and DASS-21, ISI, BIS-SF, and OHQ-SF. The internal consistency coefficients of rMEQ were Cronbach's α = 0.706 and McDonald's ω = 0.740. The sensitivity and specificity of rMEQ were 83.3%-92.7% for morning types and 86.3%-87.3% for evening types. The Turkish rMEQ has adequate psychometric properties and can be used to assess an individual's chronotype.

Intermediate versus morning chronotype has lower vascular insulin sensitivity in adults with obesity

AIM

Chronotype reflects a circadian rhythmicity that regulates endothelial function. While the morning chronotype (MORN) usually has low cardiovascular disease risk, no study has examined insulin action on endothelial function between chronotypes. We hypothesized intermediate chronotypes (INT) would have lower vascular insulin sensitivity than morning chronotype (MORN).

MATERIALS AND METHODS

Adults with obesity were classified per Morningness-Eveningness Questionnaire (MEQ) as either MORN (n = 27, 22 female, MEQ = 63.7 ± 4.7, 53.8 ± 6.7 years, 35.3 ± 4.9 kg/m2) or INT (n = 29, 23 female, MEQ = 48.8 ± 6.7, 56.6 ± 9.0 years, 35.7 ± 6.1 kg/m2). A 120 min euglycaemic-hyperinsulinaemic clamp (40 mU/m2/min, 90 mg/dl) was conducted to assess macrovascular insulin sensitivity via brachial artery flow-mediated dilation (%FMD; conduit artery), post-ischaemic flow velocity (resistance arteriole), as well as microvascular insulin sensitivity via contrast-enhanced ultrasound [e.g. microvascular blood volume (perfusion)]. Fasting plasma arginine and citrulline, as well as fasting and clamp-derived plasma endothelin-1 and nitrate/nitrite, were assessed as surrogates of vasoconstriction and nitric oxide-mediated vasodilation. Aerobic fitness (VO2max) and body composition (dual-energy X-ray absorptiometry) were also collected.

RESULTS

MORN had a higher VO2max compared with INT (p < .01), although there was no difference in fat mass. While fasting FMD was similar between groups, insulin lowered FMD corrected to shear stress and microvascular blood volume in INT compared with MORN after co-varying for VO2max (both p ≤ .02). INT also had a lower fasting nitrate (p = .03) and arginine (p = .07). Higher MEQ correlated with elevated FMD (r = 0.33, p = .03) and lower post-ischaemic flow velocity (r = -0.33, p = .03) as well as shear rate (r = -0.36, p = .02) at 120 min.

CONCLUSION

When measured during the morning, INT had a lower vascular insulin sensitivity than MORN. Additional work is needed to understand endothelial function differences among chronotypes to optimize cardiovascular disease risk reduction.

The effect of circadian timing program for evening-chronotype individuals with obesity on obesity management and sleep quality: A randomized controlled trial

OBJECTIVES

The study aimed to investigate the effect of the circadian timing program (SİZAP) developed for evening-chronotype individuals with obesity on obesity management and sleep quality.

METHODS

This single-site, randomized controlled trial with an experimental research design was registered in ClinicalTrials.gov. It was reported in accordance with the "Consolidated Standards of Reporting Trials" (CONSORT) randomized controlled trial guidelines. The study sample consisted of 38 evening-chronotype individuals with first-degree obesity, with 19 individuals in each study group. The intervention group's sleep hygiene training was conducted and their lifestyle changes were ensured through SİZAP. The control group followed their normal daily lifestyle. No intervention was made in terms of the dietary practices of both groups. Study data were collected using the personal information form, the anthropometric measurement form, the Horne and Ostberg Morning and Evening Questionnaire (MEQ), the Impact of weight on quality of life-lite (IWQOL-lite), the Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale (ESS), the sleep diary, and the data tracked via the website and smart bracelets.

RESULTS

It was determined that the participants in the SİZAP group had a statistically significant decrease in the anthropometric measurements and daytime sleepiness (p < 0.05). The sleep quality scores and the scores of the bodily functions sub-dimension of the quality of life scale were significantly better in the intervention group than in the control group (p < 0.05).

CONCLUSION

It was found that SİZAP is effective in obesity management in evening-chronotype individuals and increases weight loss success and sleep quality.

Eating time variation from weekdays to weekends and its association with dietary intake and BMI in different chronotypes: findings from National Health and Nutrition Examination Survey (NHANES) 2017-2018

Evidence suggests that differences in meal timing between weekends and weekdays can disrupt the body's circadian rhythm, leading to a higher BMI. We aimed to investigate the associations between mealtime variation from weekdays to weekends (eating midpoint jetlag), dietary intake and anthropometric parameters, based on individuals' chronotype. The study utilised data from National Health and Nutrition Examination Survey 2017-2018. Food consumption was estimated by weighted average of participants' food intake on weekdays and weekends. Eating midpoint jetlag, defined as the difference between the midpoint of the first and last mealtimes on weekends and weekdays, was calculated. Chronotype was assessed by participants' mid-sleep time on weekends, adjusted for sleep debt. Linear regression analysis was conducted to investigate the associations between variables. The sample was categorised into chronotype tertiles. Among individuals in the third chronotype tertile, there was a positive association between eating midpoint jetlag and BMI (β = 1·2; 95 % CI (1·13, 1·27)). Individuals in the first tertile showed a positive association between eating midpoint jetlag and energy (β = 96·9; 95 % CI (92·9, 101·7)), carbohydrate (β = 11·96; 95 % CI (11·2, 12·6)), fat (β = 3·69; 95 % CI (3·4, 3·8)), cholesterol (β = 32·75; 95 % CI (30·9, 34·6)) and sugar (β = 8·84; 95 % CI (8·3, 9·3)) intake on weekends. Among individuals with an evening tendency, delaying meals on weekends appears to be linked to a higher BMI. Conversely, among individuals with a morning tendency, eating meals later on weekends is associated with higher energetic intake on weekends.

Meal timing and its role in obesity and associated diseases

Meal timing emerges as a crucial factor influencing metabolic health that can be explained by the tight interaction between the endogenous circadian clock and metabolic homeostasis. Mistimed food intake, such as delayed or nighttime consumption, leads to desynchronization of the internal circadian clock and is associated with an increased risk for obesity and associated metabolic disturbances such as type 2 diabetes and cardiovascular diseases. Conversely, meal timing aligned with cellular rhythms can optimize the performance of tissues and organs. In this review, we provide an overview of the metabolic effects of meal timing and discuss the underlying mechanisms. Additionally, we explore factors influencing meal timing, including internal determinants such as chronotype and genetics, as well as external influences like social factors, cultural aspects, and work schedules. This review could contribute to defining meal-timing-based recommendations for public health initiatives and developing guidelines for effective lifestyle modifications targeting the prevention and treatment of obesity and associated metabolic diseases. Furthermore, it sheds light on crucial factors that must be considered in the design of future food timing intervention trials.

Chrononutrition in traditional European medicine-Ideal meal timing for cardiometabolic health promotion

Meal timing plays a crucial role for cardiometabolic health, given the circadian regulation of cardiometabolic function. However, to the best of our knowledge, no concept of meal timing exists in traditional European medicine (TEM). Therefore, in this narrative review, we aim to define the optimal time slot for energy intake and optimal energy distribution throughout the day in a context of TEM and explore further implications. By reviewing literature published between 2002 and 2022, we found that optimal timing for energy intake may be between 06:00 and 09:00, 12:00 and 14:00, and between 15:00 and 18:00, with high energy breakfast, medium energy lunch and low energy dinner and possibly further adjustments according to one's chronotype and genetics. Also, timing and distribution of energy intake may serve as a novel therapeutic strategy to optimize coction, a concept describing digestion and metabolism in TEM. Please cite this article as: Eberli NS, Colas L, Gimalac A. Chrononutrition in traditional European medicine-Ideal meal timing for cardiometabolic health promotion. J Integr Med. 2024; 22(2);115-125.

Personalized laboratory medicine in the digital health era: recent developments and future challenges

Interpretation of laboratory data is a comparative procedure and requires reliable reference data, which are mostly derived from population data but used for individuals in conventional laboratory medicine. Using population data as a "reference" for individuals has generated several problems related to diagnosing, monitoring, and treating single individuals. This issue can be resolved by using data from individuals' repeated samples, as their personal reference, thus needing that laboratory data be personalized. The modern laboratory information system (LIS) can store the results of repeated measurements from millions of individuals. These data can then be analyzed to generate a variety of personalized reference data sets for numerous comparisons. In this manuscript, we redefine the term "personalized laboratory medicine" as the practices based on individual-specific samples and data. These reflect their unique biological characteristics, encompassing omics data, clinical chemistry, endocrinology, hematology, coagulation, and within-person biological variation of all laboratory data. It also includes information about individuals' health behavior, chronotypes, and all statistical algorithms used to make precise decisions. This approach facilitates more accurate diagnosis, monitoring, and treatment of diseases for each individual. Furthermore, we explore recent advancements and future challenges of personalized laboratory medicine in the context of the digital health era.

Determination of the relationship between body composition and nutritional habits and chronotype in healthy Turkish adults

This cross-sectional study aims to determine the relationship between chronotype characteristics, dietary habits, and body composition in 110 adults, of which 75.5% are female, residing in Mersin, Türkiye. Data collection included a descriptive information form, the Morningness-Eveningness Scale for assessing chronotype, a detailed 24-hour dietary record for evaluating dietary intake, and Bioelectrical Impedance Analysis for accurate anthropometric measurements of body composition. The evening types had higher BMI, body weight, waist circumference, hip circumference, total fat mass, and lower body water ratio than the morning types. Positive correlations were found between sleep duration and body mass index, total fat mass, and fat percentage. The evening types tended to skip breakfast more frequently and had higher energy intake during dinners and snacks. Additionally, the evening types consumed more lipids, carbohydrates, sodium, and saturated and polyunsaturated fatty acids. These findings suggest that chronotype influences anthropometric measurements, nutritional habits, and meal energy distribution. These findings highlight the importance of considering chronotype characteristics to understand how body composition and dietary patterns interact, underscoring the need for customized interventions to promote healthier lifestyles.

Association of Chrononutrition Indices with Anthropometric Parameters, Academic Performance, and Psychoemotional State of Adolescents: A Cross-Sectional Study

Adolescents are an at-risk group for circadian misalignment. The contribution of sleep-wake rhythm instability to the psychoemotional, cognitive, and weight disorders of adolescents has been studied in sufficient detail. At the same time, there is insufficient information about the association between chrononutrition indices and the well-being of adolescents. The aim of this study is to investigate the relationship between chrononutrition indices and academic achievement, psychoemotional state, and anthropometric indicators in adolescents. The study involved 12,759 students in grades 6-11 of secondary schools, aged 14.2 ± 1.7 years old; 57.2% of whom were girls. Participants provided personal data, frequency and time of meals during the day and at night, on weekdays and weekends, and completed the Zung Self-Rating Depression Scale and the Yale Food Addiction Scale. There is a U-shaped association between eating mid-phase (EPFc), eating jetlag (EJL), and eating window (EW) with GPA, ZSDSI, and FA. At the same time, the frequency of night eating (NE) is linearly associated with the studied parameters. NE is the strongest predictor of ZSDSI (β = 0.24), FA (β = 0.04), and GPA (β = -0.22). EPFc, EJL, and EW practically do not differ in the strength of their association with the studied indicators. ZSDSI is most closely associated with the chrononutrition indices. There is a weak negative association between BMI and EW (β = -0.03) and NE (β = -0.04). Thus, circadian eating disorders are more often observed in adolescents with poor academic performance, high levels of depression, and food addiction.

Exercise blood pressure and heart rate responses to graded exercise testing in intermediate versus morning chronotypes with obesity

Exaggerated exercise blood pressure (BP) is linked to cardiovascular disease (CVD). Although evening chronotypes have greater CVD risk than morning (Morn) types, it is unknown if exercise BP differs in intermediate (Int) types. Adults with obesity were classified as either Morn [n = 23 (18 females), Morning-Eveningness Questionnaire (MEQ) = 63.96 ± 1.0, 54.74 ± 1.4 yr, 33.7 ± 0.6 kg/m2] or Int [n = 23 (19 females), MEQ = 51.36 ± 1.1, 55.96 ± 1.8 yr, 37.2 ± 1.2 kg/m2] chronotype per MEQ. A graded, incremental treadmill test to maximal aerobic capacity (V̇o2max) was conducted. Systolic (SBP) and diastolic (DBP) blood pressure and mean arterial pressure (MAP), rate pressure product (RPP), heart rate (HR), and rate of perceived intensity (RPE) were determined at baseline, 4 min, 6 min, and maximal stages. HR recovery (HRR; maximum postexercise) was determined at 1 and 2 min postexercise. Preexercise fasted aortic waveforms (applanation tonometry), plasma leptin, nitrate/nitrite (nitric oxide bioavailability), and body composition (dual X-ray, DXA) were also collected. Int had lower V̇o2max and plasma nitrate (both P ≤ 0.02) than Morn. No difference in preexercise BP, aortic waveforms, or body composition were noted between groups, although higher plasma leptin was seen in Int compared with Morn (P = 0.04). Although Int had higher brachial DBP and MAP across exercise stages (both P ≤ 0.05) and higher HR, RPE, and RPP at 6 min of exercise (all P ≤ 0.05), covarying for V̇o2max nullified the BP, but not HR or RPE, difference. HRR was greater in Morn independent of V̇o2max (P = 0.046). Fasted leptin correlated with HR at exercise stage 4 (r = 0.421, P = 0.041) and 6 min (r = 0.593, P = 0.002). This observational study suggests that Int has exaggerated BP and HR responses to exercise compared with Morn, although fitness abolished BP differences.NEW & NOTEWORTHY This study compares blood pressure and heart rate responses with graded, incremental exercise between morning and intermediate chronotype adults with obesity. Herein, blood pressure responses to exercise were elevated in intermediate compared with morning chronotype, although V̇o2max abolished this observation. However, heart rate responses to exercise were higher in intermediate vs. morning chronotypes independent of fitness. Collectively, this exercise hemodynamic response among intermediate chronotype may be related to reduced aerobic fitness, altered nitric oxide metabolism, and/or elevated aortic waveforms.

Differences in Dietary Intake, Eating Occasion Timings and Eating Windows between Chronotypes in Adults Living with Type 2 Diabetes Mellitus

Chronotype studies investigating dietary intake, eating occasions (EO) and eating windows (EW) are sparse in people with type 2 Diabetes mellitus (T2DM). This analysis reports data from the CODEC study. The Morningness-Eveningness questionnaire (MEQ) assessed chronotype preference. Diet diaries assessed dietary intake and temporal distribution. Regression analysis assessed whether dietary intake, EW, or EO differed by chronotype. 411 participants were included in this analysis. There were no differences in energy, macronutrient intake or EW between chronotypes. Compared to evening chronotypes, morning and intermediate chronotypes consumed 36.8 (95% CI: 11.1, 62.5) and 20.9 (95% CI: -2.1, 44.1) fewer milligrams of caffeine per day, respectively. Evening chronotypes woke up over an hour and a half later than morning (01:36 95% CI: 01:09, 02:03) and over half an hour later than intermediate chronotypes (00:45 95% CI: 00:21; 01:09. Evening chronotypes went to sleep over an hour and a half later than morning (01:48 95% CI: 01:23; 02:13) and an hour later than intermediate chronotypes (01:07 95% CI: 00:45; 01:30). Evening chronotypes' EOs and last caffeine intake occurred later but relative to their sleep timings. Future research should investigate the impact of chronotype and dietary temporal distribution on glucose control to optimise T2DM interventions.

Associations between sleep characteristics and glycemic variability in youth with type 1 diabetes

OBJECTIVE

This study aimed to determine sleep characteristics and their associations with glycemic variability in youth with type 1 diabetes (T1D).

MATERIAL AND METHODS

This cross-sectional study conducted at two pediatric diabetes centers in Istanbul, Turkey, included 84 children with T1D (mean age 10.5 years). Sleep characteristics and glycemic variability were determined by actigraphy, DSM-5 Level 2-Sleep Disturbance Scale Short Form and continuous glucose monitoring. Circadian preference was evaluated by the Children's Chronotype Questionnaire. Sleep disturbances were assessed by the. The sleep quality was determined by actigraphy-derived sleep measures.

RESULTS

Eighty-eight percent of participants had insufficient age-appropriate total sleep time (TST) (<9 h for 6-13-year-olds and <8 h for 14-17-year-olds). Chronotype was classified as intermediate in 50%, evening in 45.2%, and morning in 4.8%. A higher chronotype score indicating a stronger eveningness preference was associated with more time spent in hypoglycemia (β = 0.433, p = 0.002). On nights when participants had lower sleep efficiency and longer sleep onset latency, they had significantly higher overnight glycemic variability (β = -0.343, p = 0.016, β = 0.129, p = 0.017, respectively). Prolonged nocturnal wake duration was significantly associated with more time spent in daytime hypoglycemia (β = 0.037, p = 0.046) and higher overnight glycemic variability (J index, β = 0.300, p = 0.015). The associations between TST and glycemic variability indices were not significant.

CONCLUSIONS

Sleep quality rather than TST was significantly associated with glycemic variability in children with T1D. Eveningness preference might contribute to an increased risk of hypoglycemia. Addressing sleep patterns and chronotypes can be crucial in management plans for youth with T1D.

PPARG stimulation restored lung mRNA expression of core clock, inflammation- and metabolism-related genes disrupted by reversed feeding in male mice

The circadian rhythm system regulates lung function as well as local and systemic inflammations. The alteration of this rhythm might be induced by a change in the eating rhythm. Peroxisome proliferator-activated receptor gamma (PPARG) is a key molecule involved in circadian rhythm regulation, lung functions, and metabolic processes. We described the effect of the PPARG agonist pioglitazone (PZ) on the diurnal mRNA expression profile of core circadian clock genes (Arntl, Clock, Nr1d1, Cry1, Cry2, Per1, and Per2) and metabolism- and inflammation-related genes (Nfe2l2, Pparg, Rela, and Cxcl5) in the male murine lung disrupted by reversed feeding (RF). In mice, RF disrupted the diurnal expression pattern of core clock genes. It decreased Nfe2l2 and Pparg and increased Rela and Cxcl5 expression in lung tissue. There were elevated levels of IL-6, TNF-alpha, total cells, macrophages, and lymphocyte counts in bronchoalveolar lavage (BAL) with a significant increase in vascular congestion and cellular infiltrates in male mouse lung tissue. Administration of PZ regained the diurnal clock gene expression, increased Nfe2l2 and Pparg expression, and reduced Rela, Cxcl5 expression and IL-6, TNF-alpha, and cellularity in BAL. PZ administration at 7 p.m. was more efficient than at 7 a.m.

The association of dietary approaches to stop hypertension (DASH) and Mediterranean diet with mental health, sleep quality and chronotype in women with overweight and obesity: a cross-sectional study

PURPOSE

Mental and sleep disorders are global public health problems, especially in Middle Eastern countries, and are significantly associated with circadian rhythm. This study sought to investigate the association between the dietary approaches to stop hypertension (DASH) and Mediterranean diet scores and mental health, sleep quality, and circadian rhythm.

METHODS

We enrolled 266 overweight and obese women, and depression, anxiety, and stress scale (DASS) score, Pittsburgh Sleep Quality Index (PSQI), and Morning-Evening Questionnaire (MEQ), were assessed. The Mediterranean and DASH diet score was measured using a validated semi-quantitative Food Frequency Questionnaire (FFQ). The physical activity was evaluated using the International Physical Activity Questionnaire (IPAQ). Analysis of variance and analysis of covariance, chi-square, and multinomial logistic regression tests were used as appropriate.

RESULTS

Our results showed that there was a significant inverse association between adherence to the Mediterranean diet and mild and moderate anxiety scores (p < 0.05). In addition, there was an inverse association between adherence to the DASH diet and the risk of severe depression and extremely severe stress scores (p < 0.05). Moreover, higher adherence to both dietary scores was associated with good sleep quality (p < 0.05). There was a significant relationship between circadian rhythm and the DASH diet (p < 0.05).

CONCLUSION

A significant association exists between a DASH and Mediterranean diet with sleep status, mental health, and chronotype in women of childbearing age with obesity and overweight.

LEVEL OF EVIDENCE

Level V, Cross-sectional observational study.

Chronotype as a predictor of weight loss and body composition improvements in women with overweight or obesity undergoing a very low-calorie ketogenic diet (VLCKD)

BACKGROUND & AIM

Recent studies reported that chronotype play a role in the development of metabolic comorbidities and in determining dietary habits in obesity. However, little is known if chronotype could predict the efficacy of nutritional approaches for obesity. The aim of this study was to investigate whether chronotype categories can have a role in determining the efficacy of very low-calorie ketogenic diet (VLCKD) in terms of weight loss and changes of body composition in women with overweight or obesity.

METHODS

In this retrospective study we analyzed data from 248 women (BMI 36.03 ± 5.20 kg/m2, aged 38.76 ± 14.05 years) clinically referred for weight loss and who completed a VLCKD program. In all women, we assessed anthropometric parameters (weight, height, and waist circumference), body composition and phase angle (through bioimpedance analysis, Akern BIA 101) at the baseline and after 31 days of active phase of VLCKD. Chronotype score was assessed using Morningness-Eveningness questionnaire (MEQ) at baseline.

RESULTS

After 31 days of active phase of VLCKD all enrolled women experienced significant weight loss (p < 0.001) and reduction of BMI (p < 0.001), waist circumference (p < 0.001), fat mass (kg and %) (p < 0.001), and free fat mass (kg) (p < 0.001). Women with evening chronotype experienced significantly less weight loss (p < 0.001) and reduced fat mass (kg and %) (p < 0.001), increased fat free mass (kg and %) (p < 0.001) and phase angle (p < 0.001) than women with morning chronotype. In addition, chronotype score correlated negatively with percentage changes in weight (p < 0.001), BMI (p < 0.001), waist circumference (p < 0.001) and fat mass (p < 0.001) and positively with fat free mass (p < 0.001) and phase angle (p < 0.001) from baseline to the 31st day of active phase of VLCKD. Using a linear regression model, chronotype score (p < 0.001) was the main predictors of weight loss achieved with VLCKD.

CONCLUSION

Evening chronotype is associated with a lower efficacy in terms of weight loss and improvements of body composition after VLCKD in obesity.

Circadian rhythm sleep-wake disorders and the risk of dyslipidemia among railway workers in southwest China: A cross-sectional study

Railway workers are more likely to have an irregular work schedule, which had an effect on their circadian rhythm of sleep, and may lead to circadian rhythm sleep-wake disorders (CRSWDs). The association between CRSWDs and dyslipidemia in railway workers is poorly understood. The objective of this research is to study the association between CRSWDs and the risk of dyslipidemia. This cross-sectional study was conducted among railway workers in Southwest China. CRSWDs were assessed by the morningness-eveningness questionnaire self-assessment version (MEQ-SA). The blood samples were collected in the morning and the lipids of participants were measured. Associations of CRSWDs with dyslipidemia and its components were analyzed. A total of 8079 participants were enrolled in this study, and the results revealed that shift work sleep disorder (SWD) and advanced sleep-wake phase disorder (ASWPD) were associated with a higher risk of dyslipidemia (OR 1.17, 95%CI 1.06-1.29, P < 0.01; OR 1.68, 95%CI 1.09-2.64, P < 0.05) after adjusting for sociodemographic characteristics and lifestyles, in comparison with the control group. As for its components, the SWD group was associated with a higher risk of elevated total cholesterol, triglycerides, and low-density lipoprotein than the control group, while the ASWPD group was associated with a higher risk of elevated total cholesterol, and low-density lipoprotein (P < 0.05). In summary, SWD and ASWPD participants were associated with a higher risk of dyslipidemia in railway workers in Southwest China.Abbreviation: TG: triglyceride; TC: Total cholesterol; LDL-C: low-density lipoprotein cholesterol; HDL-C: high-density lipoprotein cholesterol; FPG: fasting plasma glucose. MEQ-SA: morningness-eveningness questionnaire self-assessment version; IPW: inverse-probability weighting; HDS: healthy diet scores; FFQ: food frequency; PA: physical activity; IQAP-SF: international physical activity questionnaire short form; MET-min/wk: metabolic equivalent task minutes per week; BMI: body mass index; SBP: systolic blood pressure; DBP: diastolic blood pressure; HBP: hypertension; DM: diabetes; CVD: cerebrovascular disease; OR: odds ratios; CI: confidence intervals.

Cross-sectional interrelationships between chronotype, obstructive sleep apnea and blood pressure in a middle-aged community cohort

Chronotype is linked to adverse health measures and may have important associations with obstructive sleep apnea and blood pressure, but data are limited. This study aimed to determine the separate and combined associations of chronotype with obstructive sleep apnea and blood pressure in a middle-aged community population. Adults (n = 811) from the Raine Study (female = 59.2%; age mean [range] = 56.6 [42.1-76.6] years) were assessed for chronotype (Morningness-Eveningness Questionnaire), blood pressure and hypertension (doctor diagnosed or systolic blood pressure ≥ 140 mmHg and/or diastolic ≥ 90 mmHg), and obstructive sleep apnea at different in-laboratory apnea-hypopnea index thresholds (5, 10, 15 events per hr). Linear and logistic regression models examined relationships between chronotype and the presence and severity of obstructive sleep apnea, blood pressure, hypertension, and blood pressure stratified by obstructive sleep apnea severity at above-mentioned apnea-hypopnea index thresholds. Covariates included age, sex, body mass index, alcohol consumption, smoking, physical activity, sleep duration, anti-hypertensive medication, insomnia, and depressive symptoms. Most participants were categorised as morning (40%) or intermediate (43%), with 17% meeting criteria for evening chronotypes. Participants with apnea-hypopnea index ≥ 15 events per hr and morning chronotype had higher systolic (9.9 mmHg, p < 0.001) and a trend for higher diastolic blood pressure (3.4 mmHg, p = 0.07) compared with those with an evening chronotype, and higher systolic blood pressure compared with those with an intermediate chronotype (4.8 mmHg, p = 0.03). Across chronotype categories, no differences in systolic or diastolic blood pressure or odds of hypertension were found at apnea-hypopnea index thresholds of ≥ 5 or ≥ 10 events per hr. Among participants with apnea-hypopnea index ≥ 15 events per hr, systolic blood pressure is higher in those with a morning chronotype than evening and intermediate chronotypes. Assessment for morning chronotype may improve risk stratification for hypertension in patients with obstructive sleep apnea.

Erwin M, Olmstead R, Jean-Louis G, Parthasarathy S, D. Youngstedt S. Comparisons of Sleep, Demographics, and Health-Related Variables in Older Long and Average Duration Sleepers

Introduction  Long sleep duration is associated with many health risks, particularly in older adults, but little is known about other characteristics associated with long sleep duration. Methods  Across 5 sites, adults aged 60-80 years who reported sleeping 8-9 h ("long sleepers", n = 95) or 6-7.25 h ("average sleepers", n = 103) were assessed for two weeks using actigraphy and sleep diary. Demographic and clinical characteristics, objective sleep apnea screening, self-reported sleep outcomes, and markers of inflammation and glucose regulation were measured. Results  Compared to average sleepers, long sleepers had a greater likelihood of being White and unemployed and/or retired. Long sleepers also reported longer time in bed, total sleep time and wake after sleep onset by sleep diary and by actigraphy. Other measures including medical co-morbidity, apnea/hypopnea index, sleep related outcomes such as sleepiness, fatigue, depressed mood, or markers of inflammation and glucose metabolism did not differ between long and average sleepers. Conclusion  Older adults with long sleep duration were more likely to be White, report unemployment and retirement suggesting the social factors or related sleep opportunity contributed to long sleep duration in the sample. Despite known health risks of long sleep duration, neither co-morbidity nor markers of inflammation or metabolism differed in older adults with long sleep duration compared with those with average sleep duration.

The Relationship between Sleep, Chronotype, and Dental Caries-A Narrative Review

This article provides an overview of how sleep and circadian rhythm disturbances mutually influence the occurrence of dental caries and how it is possible to reduce the risk of circadian rhythm disturbances, sleep, and associated adverse effects. Dental caries is a global problem worldwide that contributes to sociological limitations. Numerous factors influence the occurrence of dental caries, from socioeconomic factors to cariogenic bacteria, dietary habits, and oral hygiene. However, sleep disorders and circadian rhythm disturbances represent a new approach in the fight against the increasing prevalence of dental caries worldwide. Bacteria in the oral cavity and the oral microbiome are mainly responsible for the development of caries, and saliva plays an important role in their regulation. The circadian rhythm regulates numerous physiological functions, including sleep and saliva production. Disturbances in sleep and circadian rhythms affect saliva production, which impacts the development of dental caries, as saliva is necessary for regulating and maintaining oral health, especially for controlling oral infections. A person's preference for a particular time of day depends on the circadian rhythm called chronotype. Individuals with an evening chronotype have a less healthy lifestyle that can lead to a higher caries risk than individuals with a morning chronotype. Because circadian rhythms are critical to maintaining sleep homeostasis and oral health, sleep disturbances can disrupt circadian rhythms and lead to a vicious cycle.

Vitamin D and chronotype: is there any relationship in individuals with obesity?

PURPOSE

Chronotype is the attitude to perform most of the daily activities in the morning ("morning chronotype", MC) or in the evening ("evening chronotype", EC). The latter, as well as vitamin D deficiency, has been associated with an increased risk of obesity-related complications, likely through the promotion of insulin resistance. Therefore, we aimed to investigate whether there is any relationship between vitamin D (25-OH-D) and chronotype in individuals with obesity.

METHODS

In this cross-sectional study, we enrolled 59 individuals (43.1 ± 13 years; 17M/42F) with obesity. Anthropometric parameters, lifestyle habits, personal medical history, chronotype, insulin resistance, and 25-OH-D were assessed.

RESULTS

Individuals with EC presented significantly higher BMI than MC (p < 0.001), greater waist (p = 0.012), and hip circumferences (p = 0.001). Individuals with EC showed significantly lower insulin sensitivity (p = 0.017) and 25-OH-D than MC. In addition, the prevalence of vitamin D deficiency and impaired fasting glucose was significantly higher in EC than in MC. 25-OH-D directly correlated with chronotype score (r = 0.351; p = 0.019) whereas inversely with BMI (r = - 0.363; p = 0.016). The regression analysis showed that BMI was most tightly associated with 25-OH-D concentrations (β = - 0.323, p = 0.032), followed by chronotype score (β = 0.340, p = 0.042). Using chronotype score as the dependent variable, BMI significantly predicted a lower chronotype score (β = - 0.586, p < 0.001).

CONCLUSION

The present study showed that 25-OH-D, as well as chronotype, correlate independently with obesity.

Bidirectional mediation of evening energy proportion and chronotype on their associations with blood lipid levels in a Chinese population

The bidirectional relationship between chronotype and meal energy distribution, and the effect of their relationship on blood lipid level has not been investigated. This study aims to test and compare the bidirectional mediating effects of chronotype and meal energy distribution on blood lipid levels. Data of 9376 adult participants from 2018 wave of the China Health and Nutrition Survey (CHNS) were analysed. Two mediation models were tested and compared: one with Evening energy proportion (Evening EI%) as mediator of the association between adjusted mid-sleep time on free days (MSF_a) and blood lipid levels and the other with MSF_a as mediator of the association of Evening EI% with blood lipid levels. The mediating effect of Evening EI% on the association between MSF_a and TC, LDL-C and non-HDL-C were significant (p < .001, p = .001, and p = .002, respectively). The mediating effect of MSF_a on the association between Evening EI% and TC, LDL-C and non-HDL-C were significant (p = .006, p = .035, and p < .001 respectively). Evening EI% had a larger standardized mediation effect compared to MSF_a. The bidirectional mediation effect suggests a reinforcement mechanism, in which later chronotype and higher Evening EI% reciprocally influence their negative impact on elevated blood lipid levels, leading to higher risk of cardiovascular diseases in the general population.

Physiological Rhythms and Biological Variation of Biomolecules: The Road to Personalized Laboratory Medicine

The concentration of biomolecules in living systems shows numerous systematic and random variations. Systematic variations can be classified based on the frequency of variations as ultradian (<24 h), circadian (approximately 24 h), and infradian (>24 h), which are partly predictable. Random biological variations are known as between-subject biological variations that are the variations among the set points of an analyte from different individuals and within-subject biological variation, which is the variation of the analyte around individuals’ set points. The random biological variation cannot be predicted but can be estimated using appropriate measurement and statistical procedures. Physiological rhythms and random biological variation of the analytes could be considered the essential elements of predictive, preventive, and particularly personalized laboratory medicine. This systematic review aims to summarize research that have been done about the types of physiological rhythms, biological variations, and their effects on laboratory tests. We have searched the PubMed and Web of Science databases for biological variation and physiological rhythm articles in English without time restrictions with the terms “Biological variation, Within-subject biological variation, Between-subject biological variation, Physiological rhythms, Ultradian rhythms, Circadian rhythm, Infradian rhythms”. It was concluded that, for effective management of predicting, preventing, and personalizing medicine, which is based on the safe and valid interpretation of patients’ laboratory test results, both physiological rhythms and biological variation of the measurands should be considered simultaneously.

The relationship between chronotype and obesity: A systematic review

Referring to the hours during a day when a person's physical and cognitive functions are active, the chronotype indicates the differences in individual preferences in sleep timing and other behaviors. The fact that the evening chronotype has been associated with adverse health outcomes has raised the issue of relationship between chronotype and obesity. This study aims to synthesize the evidence regarding the relationship between chronotype and obesity. As part of the study, the PubMed, OVID-LWW, Scopus, Taylor & Francis, ScienceDirect, MEDLINE Complete, Cochrane Library and ULAKBIM databases were screened for the articles published between January 01, 2010 and December 31, 2020. The quality of each study was assessed independently by the two researchers using the "Quality Assessment Tool for Quantitative Studies." Upon evaluating the screening results, a total of seven studies, one of high quality and six of medium quality, were included in the systematic review. The rate of the minor allele (C) genes, which have been associated with obesity, and SIRT1-CLOCK genes, which have an additional effect in favor of resistance against weight loss, is higher in individuals of evening chronotype, and such individuals have been observed to have significantly higher resistance to weight loss. The evening chronotype individuals have been associated with a higher homeostasis model assessment (HOMA) value, higher plasma ghrelin levels, and a tendency toward a higher body mass index (BMI). The evening chronotypes have been reported to adhere less to a healthy diet and have more unhealthy behaviors and eating patterns. A diet adjusted to the chronotype has been seen to be more effective than conventional hypocaloric diet therapy in terms of anthropometric parameters. Most people who eat their main meals late are of evening chronotype, and such people have been determined to lose significantly less weight than those who eat early. It has been shown that bariatric surgery is less effective in weight loss in evening chronotype patients than in morning chronotype patients. The evening chronotypes are less successful in adapting to weight loss treatments and long-term weight control than the morning chronotypes.

Time-related meal patterns and breakfast quality in a sample of Iranian adults

BACKGROUND

Some evidence shows that meal timing is associated with diet quality. We aimed to investigate the relationship between meal timing and breakfast quality in a sample of Iranian adults.

METHODS

This cross-sectional study was conducted on 850 men and women living in Tehran, Iran. Dietary data was recorded by three non-consecutive 24-h dietary recalls. The Breakfast Quality Index (BQI) was calculated. Time-related meal patterns included the interval between the first and last meal (eating and fasting window), frequency of meals, length of sleep, and time of first and last eating occasion. The multiple linear regression analysis was used to identify the relationships between time-related meal patterns and BQI.

RESULTS

The mean (95% CI) of BQI was 4.52 (4.45-4.65) and the maximum was 8. Bread, cheese, vegetables, fruits, energy, and carbohydrate intake showed positive associations with BQI scores. Longer fasting time showed a positive association with fruits (β (CI 95%)) (0.11 (0.0003-0.005), and vegetable consumption (0.12 (0.009-0.07)) and BQI score (0.39 (0.001-0.06)). Time of first eating occasions indicated a negative association with protein and fat intake and BQI score. Time of last eating occasions showed a positive association with vegetables consumption and BQI score. The longer length of sleep was associated with a higher BQI score. The frequency of meals was significantly and positively related to energy and macronutrients intake and BQI.

CONCLUSION

Earlier first and last meal, longer sleep length, longer fasting window, and a greater meal frequency were associated with a better breakfast quality.

Chronotypes and their Association with Obesity-Related Lifestyle Behaviors among Young Female Adults

Circadian rhythms have emerged as key influences on lifestyle behaviors. Circadian rhythms vary inter-individually, and people can be stratified by circadian preference, known as their chronotype, from extreme morning types to extreme evening types. Young adults undergo chronotype changes that involve shifts from morning to evening types. We aimed to examine the association between chronotype and obesity-related lifestyle behaviors, including dietary intake, physical activity, and sleep patterns, among young females. A total of 387 college female students aged 18-25 years completed this cross-sectional study. The participants were classified into three groups (morning, intermediate, and evening types) according to the Morningness-Eveningness Questionnaire (MEQ; long version) score. Each individual's anthropometry and body composition were measured. Dietary intakes were assessed using a 24-h dietary recall. The Bouchard Three-Day Physical Activity Record was used to assess physical activity levels. Sleep patterns were evaluated using the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). The differences between chronotype groups were tested using a Chi-square test and one-way ANOVA. The chronotypes were significantly associated with sleep quality (p = 0.010) and daytime sleepiness (p = 0.035). However, no significant associations between dietary intake, physical activity, and sleep duration with the chronotypes were found. Our results show that both sleep quality and daytime sleepiness were associated with the chronotypes. Further research is warranted to identify the potential bidirectional associations between circadian rhythms and lifestyle behaviors among different age groups.

To what extent is circadian phase predictive of subjective jet lag in long-haul cabin crew pre- and post-trip?

Long-haul cabin crew regularly report misalignment between their circadian phase and the external world (i.e. jet lag). The extent to which changes in circadian phase relate to reported levels of jet lag remains unclear. The main aim of the present study was first to evaluate the relationship between objective (circadian phase) and subjective jet lag and second to explore the relative role of both subjective and objective psycho-behavioural factors in predicting the subjective experience of jet lag. Twenty-eight long-haul cabin crew completed questionnaires measuring diurnal preference, trip characteristics and subjective jet lag as a single and as a multidimensional measure. Sleep was monitored using actigraphy and urinary melatonin peak time was measured, at baseline (T1), e.g. before a long-haul trip and post-trip on the crew's first recovery day (T2). Subjective jet lag was also measured at both time points. At T1, later circadian phase related to increased unidimensional jet lag, however, a post-trip discrepancy was found between objective and subjective uni- and multidimensional jet lag measured at T2 and change from T1 to T2. After controlling for direction and size of circadian phase, increased uni- and multidimensional subjective jet lag was predicted by depressed mood states. The regression models including phase, diurnal preference, departure time on the outbound sector and arousal levels accounted for 28% of the variance in unidimensional jet lag and 53% of the variance in multidimensional jet lag. It was concluded that there is a discordance between objective and subjective jet lag post-trip. Further, subjective jet lag in long-haul cabin crew is better explained by mood impairment than circadian phase. The results are discussed with reference to the gap between subjective and objective jet lag and the role of psychology rather than just biology in the jet lag experience. The implications for improving health and safety in the workplace, through a better understanding of the role of human factors in the management of jet lag, are discussed.

Chronotype Differences in Body Composition, Dietary Intake and Eating Behavior Outcomes: A Scoping Systematic Review

The timing and nutritional composition of food intake are important zeitgebers for the biological clocks in humans. Thus, eating at an inappropriate time (e.g., during the night) may have a desynchronizing effect on the biological clocks and, in the long term, may result in adverse health outcomes (e.g., weight gain, obesity, and poor metabolic function). Being a very late or early chronotype not only determines preferred sleep and wake times but may also influence subsequent mealtimes, which may affect the circadian timing system. In recent years, an increased number of studies have examined the relation between chronotype and health outcomes, with a main focus on absolute food intake and metabolic markers and, to a lesser extent, on dietary intake distribution and eating behavior. Therefore, this review aimed to systematically determine whether chronotype indirectly affects eating behaviors, dietary intake (timing, choice, nutrients), and biomarkers leading to body composition outcomes in healthy adults. A systematic literature search on electronic databases (PubMed, CINAHL, MEDLINE, SCOPUS, Cochrane library) was performed (International Prospective Register of Systematic Reviews number: CRD42020219754). Only studies that included healthy adults (aged >18 y), classified according to chronotype and body composition profiles, using outcomes of dietary intake, eating behavior, and/or biomarkers, were considered. Of 4404 articles, 24 met the inclusion criteria. The results revealed that late [evening type (ET)] compared with early [morning type (MT)] chronotypes were more likely to be overweight/obese with poorer metabolic health. Both MT and ET had similar energy and macronutrient intakes, consuming food during their preferred sleep-wake timing: later for ET than MT. Most of the energy and macronutrient intakes were distributed toward nighttime for ET and exacerbated by unhealthy eating behaviors and unfavorable dietary intakes. These findings from our systematic review give further insight why higher rates of overweight/obesity and unhealthier metabolic biomarkers are more likely to occur in ET.

Role of chronotype in dietary intake, meal timing, and obesity: a systematic review

CONTEXT

Recent studies show that dietary habits and obesity seem to be influenced by chronotype, which reflects an individual's preference for the timing of sleeping, eating, and activity in a 24-hour period.

OBJECTIVE

This review aimed to analyze the association of chronotype with dietary habits, namely energy and macronutrient intakes, meal timing, and eating patterns, as well as with obesity.

DATA SOURCES

PubMed/MEDLINE, LILACS, and Google Scholar databases were searched between 2004 and 2020. Study selection was performed by 2 authors independently; disagreements on eligibility of articles were resolved by a third author. After assessment of 12 060 abstracts, 43 studies (21 articles on obesity; 13 on food consumption, meal timing, and eating patterns; and 9 that addressed both obesity and dietary behavior) were included.

DATA EXTRACTION

A standard form was used to extract study design, country, number of participants, method of chronotype determination, and main findings.

DATA ANALYSIS

Approximately 95% of included studies showed an association between eveningness and at least 1 unhealthy eating habit. Morningness was associated with regular consumption of fresh and minimally processed foods. In addition, about 47% of studies showed a higher association between late types and obesity.

CONCLUSION

Late types are more likely to present unhealthy eating habits, such as eating late at night, skipping breakfast often, and eating processed/ultraprocessed foods, while early types are more likely to have healthy and protective habits, such as eating early and eating predominantly fresh/minimally processed foods. Intermediate types tend to have a pattern of health and eating more similar to early types than to late types. Late types are also more likely to present higher weight and body mass index than early or intermediate types.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021256078.

Morning chronotype is associated with higher adherence to the Mediterranean diet in a sample of Italian adults

BACKGROUND AND AIMS

A growing body of evidence has associated subjects with an evening chronotype with worse eating behaviours and poorer diet quality. However, only few studies have investigated the relationship between chronotype and Mediterranean diet (MD). The aim of this study was to better understand the chronotype influence on dietary habits and MD adherence in a large sample of Italian adults.

METHODS AND RESULTS

A total of 1247 participants (66.7% women) with a mean age of 36.1 ± 14.6 years were included in the analysis. Chronotype was classified as morning in 35.6% of subjects, intermediate in 56.7%, and evening in 7.1%. Regarding meal frequency, evening subjects showed a significantly (p < 0.05) greater tendency to skip breakfast (20.5%) than morning (6.9%) and intermediate (12%) subjects. Similarly, evening subjects were found to skip mid-morning snack more often than morning subjects (59.1% vs. 47.1%; p = 0.04), and lunch more often than intermediate subjects (8% vs. 2.8%; p = 0.01). In addition, all meals were eaten by evening subjects at a significantly delayed time, except for lunch. As to MD adherence a significant (p < 0.001) higher adherence in morning subjects (10.1 ± 2.2) compared to intermediate (9.5 ± 2.1) and evening (9.5 ± 2.2) subjects was observed. At a logistic regression analysis adjusted for possible confounding factors, morning subjects showed an increased probability (OR 1.54, 95%CI 1.19-1.99; p < 0.001) of being in the highest MD adherence tertile.

CONCLUSION

Chronotype was associated with MD adherence. In particular, morning subjects showed higher MD adherence than intermediate and evening subjects.

Enhanced fear acquisition in individuals with evening chronotype. A virtual reality fear conditioning/extinction study

Circadian rhythms have received increasing attention within the context of mental disorders. Evening chronotype has been associated with enhanced risk to develop anxiety and post-traumatic stress disorder (PTSD). The classical fear conditioning paradigm is a powerful tool to reveal key mechanisms of anxiety and PTSD. We used this paradigm to study the neurocognitive basis of the association between chronotype and fear responses in healthy humans. 20 participants with evening chronotype and 20 controls (i.e., intermediate chronotype) completed a 2-day Pavlovian fear learning and extinction virtual reality task. Participants received fear conditioning, and extinction learning on day 1. Extinction memory recall was tested on day 2. To address interactions between chronotype and time of day of the fear conditioning, and extinction performance, half of the participants were tested in the morning, and the other half in the evening. Skin conductance response (SCR) and subjective fear ratings were measured as primary outcomes. Chronotype was established via the morningness-eveningness questionnaire (MEQ). We found an overall higher SCR for fear acquisition in participants with the evening chronotype profile, compared to controls. Moreover, the higher the MEQ scores -indicative of less eveningness - the lower the SCR was. No effects of chronotype were found for extinction and extinction recall. The higher vulnerability of the evening chronotype for anxiety and related disorders may thus be explained by enhanced fear acquisition of this group.

Association between chronotype, sleep pattern, and eating behaviours in a group of Italian adults

A cross-sectional study was conducted to assess the possible relationship between chronotype, sleeping, and eating patterns in 74 Italian adults (71.6% women). Based on Morningness-Eveningness Questionnare (MEQ) score, participants were classified as morning (n = 24), intermediate (n = 25), and evening (n = 25) chronotypes. From analysis, no significant differences among chronotypes emerged for sleep habits. As to eating behaviours, the evening subjects showed a significant (p < 0.05) shift towards later hours of the day in the consumption of all meals, except dinner. In addition, the evening subjects had a later midpoint of energy intake (EI) of about 35 min and 1 h (p < 0.001), respectively, than the intermediate and morning subjects. Analysing the diet quality, morning subjects reported significantly (p = 0.030) lower consumption of sweets and sweeteners, and significantly (p = 0.035) lower intake of ultra-processed fats and seasonings. Evening subjects showed a significant delay in EI during the day, while morning subjects reported a better-quality diet.

Social jet lag and eating styles in young adults

Social jet lag refers to circadian misalignment that occurs when people shift their sleep schedules from weekdays to weekends. Social jet lag is linked with numerous negative health outcomes, with emerging research connecting social jet lag to increased consumption of unhealthy foods. Existing research has not yet examined the associations between social jet lag and eating styles (e.g., emotional eating). Emotional eating and loss of control over eating are problematic eating styles which may lead to overeating and weight gain. Conversely, intuitive eating is associated with positive health outcomes such as lower risk of obesity. The present study examined social jet lag and eating styles in a young adult sample, as emerging adulthood is an important developmental time period for establishing healthy sleep and eating habits. Results of the current study indicated that in a sample of 372 American undergraduate participants, social jet lag significantly predicted lower intuitive eating (β = -.129, p = .012) and greater emotional eating (β = .12, p = .022) when controlling for age, sex, and chronotype. It was marginally predictive of loss of control over eating (β = .102, p = .050). Sleep quantity on weekdays (not weekends) also significantly predicted intuitive eating (p = .017) and loss of control over eating (p = .044), and sleep quality significantly predicted intuitive eating (p < .001), emotional eating (p < .001), and loss of control over eating (p < .001). These findings extend our understanding of the relationship between social jet lag and eating styles in college students. Addressing social jet lag in this population is an important consideration for their cardiometabolic health and for reducing weight fluctuations.

The Effect of Chronotype on Addictive Eating Behavior and BMI among University Students: A Cross-Sectional Study

The aim of this study was to examine the effect of chronotype on addictive eating behavior and BMI in university students. A questionnaire on their sociodemographic characteristics and eating habits, as well as the three-factor eating questionnaire (TFEQ) and the morningness-eveningness questionnaire (MEQ), were given to students at Üsküdar University. Data were analyzed with IBM SPSS 26.0. This study included a total of 850 students, 46.8% of whom were male and 53.2% were female. The mean BMI was 22.94 ± 3.30 kg/m2. As the BMI values of students increased, there was a decrease of 25.6% in the TFEQ scores, regardless of gender (s = −0.256; p < 0.001), and an increase of 10.6% in their chronotype scores, meaning that the students tended to be morning types (s = 0.106; p < 0.01). A significantly negative, very weak correlation was found between the students’ TFEQ and MEQ scores (s = −0.123; p < 0.001). The students’ BMI (p < 0.01) and TFEQ scores (p < 0.001) were affected by their MEQ scores in a statistically significant way. It was found that each 1-point increase in the MEQ score led to a 4.0% increase in the BMI score and a 15.8% decrease in the TFEQ score. It was observed that the morning-type students tended to be obese in terms of their BMI, and these students demonstrated fewer addictive eating behaviors.

Effect of exercises according to the circadian rhythm in type 2 diabetes: Parallel-group, single-blind, crossover study

BACKGROUND AND AIM

To evaluate the effectiveness of structured exercise appropriate the circadian rhythm in terms of blood sample test (BST), functionality and quality of life (QoL) in individuals with type 2 diabetes.

METHODS AND RESULTS

This was a parallel-group, single-blind, crossover study. Thirty individuals with type 2 diabetes aged 35-65 years were enrolled in the study and allocated into 2 groups as the Morning Chronotype (MC) Group (n = 15) and the Evening Chronotype (EC) Group (n = 15) using Morningness-Eveningness Questionnaire which was used to determine the chronotypes. Participants were evaluated in terms of BST, functionality and QoL at the beginning of the study (T0), at 6 (T1), 12 (T2), and 18 (T3) weeks after the study started. A structured exercise program for 3 days a week over 6 weeks was applied in accordance with the chronotypes (T1-T2) and cross-controlled for the chronotypes (T2-T3). Significant differences were found in favor of the exercise given at the appropriate time for the chronotype in all parameters in both groups within groups (T0-T1-T2-T3) (p < 0.05). In the time∗group interactions, exercise in accordance with the appropriate chronotype in both groups provided the highest statistical improvement in all parameters (p < 0.05).

CONCLUSION

It was concluded that structured exercise performed at the appropriate time for chronotype improves HbA_1c, fasting blood glucose, HDL-LDL cholesterol, triglyceride, total cholesterol, functionality and quality of life in type 2 diabetes. This variation in blood values was observed to reflect the quantitative effects of exercise administered according to the circadian rhythm in individuals with type 2 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT04427488). The protocol of the study was registered at ClinicalTrials.gov (NCT04427488).

Evening chronotype is associated with severe NAFLD in obesity

BACKGROUND/OBJECTIVES

Chronotype, i.e., the individual attitude to carry out the daily activities at a certain time of the day, has been reported to play a role in metabolic diseases. Thus, the aim of our study was to investigate the association of non-alcoholic fatty liver disease (NAFLD) with chronotype categories in individuals with obesity.

SUBJECTS/METHODS

In this cross-sectional study, participants underwent to anthropometric, biochemical, and the Visceral Adiposity Index (VAI) assessment. Chronotype categories were assessed by the Horne-Ostberg Morningness-Eveningness Questionnaire (MEQ). The following indirect indices of NAFLD were calculated: Liver Fat Equation (LFE), Hepatic Steatosis Index (HSI) and Index of Non-alcoholic steatohepatitis (ION).

RESULTS

The study population consisted of 87 participants (40.3 ± 12.3 years; BMI 45.6 ± 6.3 kg/m²; 64F/23M). According to the chronotype score, 31.0% were morning (MC), 36.8% were intermediate (IC), and 32.2% evening chronotype (EC). Individuals with IC were significantly younger than those with MC and EC (p = 0.002 and p = 0.047, respectively). EC presented significantly higher BMI (p < 0.001), waist circumference (p = 0.007), and hip circumference (p = 0.001) than MC. Moreover, EC had higher BMI (p < 0.001) and waist circumference (p = 0.011) than IC. All participants presented NAFLD (HSI ≥ 36 and LFE ≥ 5). Nevertheless, only individuals with EC were above the threshold of non-alcoholic steatohepatitis evaluated as ION index (ION ≥ 50). Individuals with EC presented significantly higher VAI (p = 0.036), LFE (p = 0.034), HSI (p < 0.001) and ION (p = 0.014) than MC, also after the adjustment for age, gender, and BMI.

CONCLUSION

EC is associated with more severe NAFLD independently of age, gender, and BMI than MC and IC in individuals with obesity.

Changes in chronotype and social jetlag during adolescence and their association with concurrent changes in BMI-SDS and body composition, in the DONALD Study

BACKGROUND/OBJECTIVES

Adolescence is a critical period for both the development of overweight and the transition toward a later chronotype, often accompanied by an increase in social jetlag. This study assessed whether changes in chronotype and social jetlag, are linked to changes in body composition during adolescence.

SUBJECTS/METHODS

We used data from the DONALD open cohort study, collected between 2014 and 2019, from 213 adolescents (9-17 years at baseline, 45% females) having at least two measures of chronotype and anthropometry (N = 572). Chronotype was assessed with the Munich Chronotype Questionnaire and defined as: midpoint of sleep corrected for sleep-debt (MSFsc) accumulated over the week (later MSFsc represents later chronotype). Social jetlag (SJL) defines the difference between midpoint of sleep during week and weekend. Calculations for Fat Free Mass Index (FFMI [kg/m²)]) and Fat Mass Index (FMI) [kg/m²)]) were based on body fat percentage, weight, and height. To analyze the associations, we used linear mixed-effect regression models. Finally, the total cohort was split into three biologically relevant age groups (cut-off set at <12 years, ≥12 to ≤15 years and >15 years).

RESULTS

Median follow-up was 2.1 years. Overall, change toward a later chronotype was significantly related with an increase in FMI (ß: 0.05, 95% CI: 0.01-0.08). A 1 h increase in social jetlag predicted an increase in BMI-SDS of 0.08 SDS units (95% CI: 0.01-0.14) and in FMI of 0.04 kg/m2 (95% CI: 0.003-0.08). Associations were stronger for the age group ≥12 to ≤15 years (p for interaction: <0.001). No relationship was found with FFMI.

CONCLUSIONS

Changes in MSFsc and SJL during adolescence were associated with concurrent changes in BMI-SDS and FMI. The age ≥12 to ≤15 years appears to be a sensitive period in which chronobiological changes were clearly associated with increasing body fatness.

Prevalence of Metabolic Syndrome and Insulin Resistance in a Sample of Adult ADHD Outpatients

BACKGROUND

High prevalence of Metabolic Syndrome (MS) was found in patients with schizophrenia and bipolar disorders. Insulin Resistance (IR) seems to mediate MS role in developing cardiometabolic consequences.

AIMS

To investigate the prevalence of MS, and the role of MS components and IR surrogate indexes in determining MS in adult ADHD outpatients.

METHODS

In the present cross-sectional study, MS, defined according to the Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (ATP III), and IR surrogate indexes were assessed on a consecutive sample of adult ADHD outpatients. Logistic regression analysis was performed to evaluate the effect of each ATP III component and IR surrogate index in determining MS.

RESULTS

Seventeen out of 158 patients (10.8%, 95%CI = 0.064/0.167) fulfilled the ATP-III criteria for MS. A comprehensive comparison with prevalence in the reference population was hindered by the lack of patients over 60 in the study sample, however under this age no significant differences were found. Among MS components, blood triglycerides level (OR = 1.02, 95%CI=1.01/1.03, p = 0.001) was the main predictor for MS, followed by diastolic blood pressure (OR = 1.08, 95%CI=1.01/1.16, p = 0.024) and waist circumference (OR = 1.06, 95%CI=1.01/1.13, p = 0.029). Lipid Accumulation Product (LAP, OR = 1.0006, 95%CI=1.0003/1.0009, p < 0.001) outperformed Triglyceride-Waist Circumference (TG-WC, OR=1.03, 95%CI=1.01/1.04, p < 0.001) in predicting MS.

CONCLUSIONS

More attention should be paid not only to MS but also to each ATP III component of MS and LAP in ADHD patients both at first assessment and during follow-up process.

The association between metabolic parameters and evening chronotype and social jetlag in non-shift workers: A meta-analysis

AIMS

The aim of the study was to evaluate the association between evening chronotype and social jetlag (SJL) with obesity, blood glucose and lipid levels in non-shift working adults.

METHODS

The databases of MEDLINE, EMBASE and Cochrane Reviews were searched for studies analyzing the metabolic parameters among groups of different chronotypes or SJL until Feb 2022. Weighted mean difference (WMD) and 95% confidence intervals (CI) were used to analyze the association between these parameters and chronotypes or SJL.

RESULTS

A total of 27 studies were included in this meta-analysis. Compared with morning chronotype, the participants with evening chronotype had higher body mass index (BMI) (WMD= 0.44 kg/m², 95%CI, 0.30 to 0.57 kg/m², p<0.001), higher fasting blood glucose level (WMD= 5.83mg/dl, 95%CI, 3.27to 8.38 mg/dl, p<0.001), higher total cholesterol level (WMD= 6.63mg/dl, 95%CI, 0.69 to 12.56 mg/dl, p=0.03), and lower high density lipoprotein cholesterol (HDL-C) level (WMD= -1.80mg/dl, 95%CI, -2.30 to -1.31 mg/dl, p<0.001). Compared with the participants with small SJL, the participants with large SJL had larger waist circumference (WMD= 0.80cm, 95%CI, 0.77 to 0.83cm, p<0.001).

CONCLUSIONS

Evening chronotype and SJL were associated with obesity and unfavorable metabolic parameters of glucose and lipid metabolism.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022303401.

Snacking behavior differs between evening and morning chronotype individuals but no differences are observed in overall energy intake, diet quality, or food cravings

There is a growing body of literature that links chronotype to certain undesirable eating behaviors. However, the relationship between chronotype and dietary intake is poorly characterized among adults in the United States (U.S.). This cross-sectional study examined the associations among chronotype, snacking habits, dietary intake and quality, and food cravings. One-hundred adults living in the U.S. completed the study. Based on the Horne-Östberg Morningness-Eveningness Questionnaire score, an individual was categorized as having either a morning (M)-type, intermediate (I)-type, or evening (E)-type chronotype. Snack intake was assessed using a previously published specialized food frequency questionnaire. Sugar-sweetened beverage (SSB) intake was assessed using the updated version of the Beverage Intake Questionnaire-15. Alcohol misuse was measured using the Alcohol Use Disorders Identification Test-Consumption. Diet quality was obtained using the Diet History Questionnaire III. The validated General Food Cravings Questionnaire-Trait measured participants' food cravings. E-type individuals reported consuming snacks more often over the course of a week than M-types (p = .002) but not I-types. In terms of timing of snacking, E-type individuals consumed more snacks after dinner than M-types (p < .001). E-type individuals consumed more energy-dense snacks (p = .005), especially candies (p = .005), than M-types. However, there were no significant differences in healthy snack frequency, diet quality, energy and macronutrient intake, SSB consumption, alcohol misuse, or food cravings among chronotypes (p > .05, for all). In conclusion, E-type individuals consumed snacks more frequently and later than M-types; however, chronotype was not associated with an individual's energy intake, diet quality, and food cravings, which suggests that chronotype is negligibly associated with weight gain-related behaviors in this population.

Do Temporal Eating Patterns Differ in Healthy versus Unhealthy Overweight/Obese Individuals?

This study examined whether the temporal patterns of energy and macronutrient intake in early and late eating windows were associated with metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) among non-shift workers. A total of 299 overweight/obese non-shift workers (Age: 40.3 ± 6.9 years; 73.6% women; BMI: 31.7 ± 5.0 kg/m²) were recruited in the Klang Valley area of Malaysia. The biochemical parameters were determined from fasting blood samples, whereas information on dietary intake and timing was obtained from a 7-day diet history questionnaire. The midpoint of eating was used to determine the early and late windows. Compared to MHO non-shift workers (n = 173), MUO non-shift workers (n = 126) had lower energy intake from carbohydrates and protein during the early window. In contrast, MUO participants had greater energy intake from carbohydrates and fat during the late window. Participants with unhealthy metabolic status (regardless of their chronotypes) had similar temporal patterns of energy intake characterized by smaller energy intake during the early window and greater energy intake during the late window compared with participants with healthier metabolic status. Overall, the lowest percentile of energy intake during the early window was associated with an increased risk of MUO, after adjustment for potential confounders [odds ratio (OR) = 4.30, 95% confidence interval (CI) 1.41-13.11]. The greater the energy intake during the late window, the greater the risk of MUO (OR = 2.38, 95% CI 1.11-5.13) (OR = 2.33, 95% CI 1.03-5.32) (OR = 4.45, 95% CI 1.71-11.56). In summary, consuming less energy earlier in the day and more energy and carbohydrate later in the day was associated with a greater risk of MUO. Thus, a prospective study is needed to explore the potential role of chrono-nutrition practices in modifying risk factors to delay the transition of MHO to MUO.

No Significant Effect of the Individual Chronotype on the Result of Moderate Calorie Restriction for Obesity-A Pilot Study

BACKGROUND

Chronotype is the pattern of the circadian rhythm that allows an individual to optimize times of sleep and activity. It has been observed that chronotypes may associate with some conditions and diseases, including obesity. It is not known, however, whether chronotypes determine the effectiveness of weight loss regimens. Therefore, in the present study, we compared the outcomes of a 3-week moderate calorie restriction undertaken by individuals with obesity under the same controlled hospital conditions.

METHODS

A total of 131 participants with obesity (median BMI 40.0) were studied. The subjects underwent the same dietary intervention over 3 weeks, with a 30% reduction in daily caloric intake. The individual chronotypes were assessed by the morning and evening questionnaire (MEQ) according to Horne and Östberg. Anthropometric and biochemical parameters were assessed by routine methods.

RESULTS

Of all patients examined, 75% had the morning (lark) chronotype and 25% had the evening (owl) chronotype. These patient sub-groups did not differ in terms of demographic, anthropometric and biochemical characteristics at baseline. After 3 weeks of calorie restriction, both groups experienced a similar loss of weight and BMI (Body Mass Index) (3.4 ± 0.38% for larks vs. 4.1 ± 0.47% for owls, p = 0.45), with owls exhibiting a marginally greater loss of body fat (3.1 ± 0.79%) compared with larks (2.6 ± 0.64%), p = 0.02. On the other hand, the larks had a more discernable, but not statistically significant from owls, decrease in glycated haemoglobin and CRP (C Reactive Protein).

CONCLUSIONS

The chronotype of individuals with obesity does not have a significant effect on the magnitude of the body weight loss, but there is a tendency observed towards the reduction in body fat content in owls through changing their meal and sleep timing to earlier hours, in response to moderate calorie restriction applied under the same controlled conditions.

Is chronotype associated with dietary intake and weight gain during pregnancy? A prospective and longitudinal study

OBJECTIVES

The effects of chronotype on dietary intake and weight gain during pregnancy have not been addressed in the literature. The aim of this study was to analyze the effect of chronotype on eating patterns, energy, and macronutrient intake and distribution, as well as weight gain during pregnancy.

METHODS

This was a prospective cohort study carried out with 100 pregnant women in the first, second, and third gestational trimesters. Dietary intake was assessed by three 24-h dietary recalls in each trimester, totaling nine recalls. Energy and macronutrient intake and distribution were evaluated at meals throughout the day. Chronotype was derived from midsleep time on free days, and the scores obtained were categorized into tertiles. Recommendations from the Institute of Medicine were used to assess the adequacy of weight gain. Generalized estimating equation models were used to determine the effects of chronotype and gestational trimester on eating patterns, daily energy, macronutrient distribution, and weight gain.

RESULTS

Pregnant women with values for midsleep time on free days indicative of eveningness have breakfast later and also have higher energy and carbohydrate intake at dinner than "morning" women. Pregnant "morning" women showed better diet quality in terms of milk and dairy and saturated fat. Also, despite the tendency for all tertiles to gain excess weight during pregnancy, we found that pregnant women with a tendency to eveningness had worse adequacy of gestational weight gain in the third trimester than "morning" women (2.24 ± 0.25 versus 1.22 ± 0.14, P < 0.001).

CONCLUSION

Pregnant women with a tendency to eveningness consume breakfast later in the day and exhibit greater consumption of energy and carbohydrates in the evening, as well as a worse standard of gestational weight gain in the third trimester. Our results emphasize the importance of considering chrononutrition variables in prenatal nutritional guidelines to promote maternal and fetal health.

The Importance of Being a 'Lark' in Post-Menopausal Women with Obesity: A Ploy to Prevent Type 2 Diabetes Mellitus?

Chronotype is defined as the behavioral manifestation of circadian rhythms related to the external light–dark cycle. Evening chronotype has been associated with an increased risk of developing cardiometabolic diseases in obesity. Menopause is a lifestage associated with an increased risk of developing cardiometabolic diseases and a change in circadian rhythmicity compared to pre-menopause. However, the prevalence of chronotype categories in menopause and their role in determining menopause-related cardiometabolic risk, mostly in obesity, have not been investigated. Thus, we aimed to investigate the prevalence of chronotype categories in post-menopausal women with obesity and their role in menopause-related cardiometabolic risk. In this cross-sectional study we enrolled 49 pre-menopausal and 74 post-menopausal women with obesity. Anthropometric parameters, lifestyle habits, adherence to the Mediterranean Diet (MD), sleep quality, chronotype and the presence of type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD) were studied. No significance differences were detected in terms of lifestyle and adherence to the MD between pre- and post-menopausal women. Chronotype was classified as morning in 66 (53.6%), evening in 20 (16.3%) and intermediate in 37 (30.1%) women. In addition, pre-menopausal women with obesity showed a significantly higher chance to have an intermediate chronotype (OR = 2.21, 95% CI 1.28–3.83; p = 0.004), whereas post-menopausal women with obesity showed a trend to have a higher morning chronotype (OR = 1.42, 95% CI 0.98–2.06; p = 0.051), although this did not reach statistical significance. No significant differences were detected in terms of prevalence of evening chronotype between the two groups. However, the evening chronotype had a significantly higher risk to have T2DM compared to the morning (OR = 17.29, 95% CI 2.40–124.27; p = 0.005) and intermediate chronotypes (OR = 30.86, 95% CI 2.05–464.32; p = 0.013) in both pre- and post-menopausal women with obesity. In conclusion, the intermediate chronotype was significantly more prevalent in pre-menopausal women with obesity compared to post-menopausal women. Evening chronotype was associated to T2DM in both pre- and post-menopause. These results support the importance of including the assessment of chronotype in the management of women with obesity in post-menopause.

Effect of sleep duration on dietary intake, desire to eat, measures of food intake and metabolic hormones: A systematic review of clinical trials

BACKGROUND AND AIMS

Sleep, as well as diet and physical activity, plays a significant role in growth, maturation, health, and regulation of energy homeostasis. Recently, there is increasing evidence indicating a possible causal association between sleep duration and energy balance. We aimed to examine the relationship between sleep duration and food consumption, energy intake, anthropometric characteristics, and appetite-regulating hormones by randomized controlled trials (RCTs).

METHODS

Electronic literature searches were conducted on Medline, Web of Science, and Google Scholar until July 2020. The search was conducted with the following words: "Sleep Duration", "Circadian Rhythm", "Sleep Disorders" in combination with "Obesity", "Overweight", "Abdominal Obesity", "Physical Activity", "Energy Intake", "Body Mass Index", "Lipid Metabolism", "Caloric Restriction", Leptin, "Weight Gain", and "Appetite Regulation" using human studies.methods RESULTS: After screening 708 abstracts, 50 RCTs (7 on children or adolescents and 43 on adults) were identified and met the inclusion criteria. In general, the findings suggested that sleep restriction may leads to a significant increment in energy intake, fat intake, body weight, appetite, hunger, eating occasions, and portion size, while protein and carbohydrate consumption, total energy expenditure, and respiratory quotient remained unaffected as a result of sleep restriction. Serum leptin, ghrelin, and cortisol concentrations were not influenced by sleep duration as well.

CONCLUSION

Insufficient sleep can be considered as a contributing factor for energy imbalance, weight gain, and metabolic disorders and it is suggested that to tackle disordered eating it may be necessary to pay more attention to sleep duration.

Effects of sleep habits on acute myocardial infarction risk and severity of coronary artery disease in Chinese population

Background

Growing evidence indicates that poor sleep harms health. Early to bed and early to rise is considered as a healthy lifestyle in Chinese population. The current study aimed to examine the effects of sleep habits on acute myocardial infarction (AMI) risk and severity of coronary artery disease (CAD) in Chinese population from two centers.

Methods

A total of 873 patients including 314 AMI cases and 559 controls were recruited from the inpatient cardiology department of the Affiliated Jiangning Hospital and the First Affiliated Hospital of Nanjing Medical University. 559 controls included 395 CAD cases and 164 non-CAD cases. We used a 17-item sleep factors questionnaire (SFQ) to evaluate sleep habits comprehensively by face-to-face interview. The severity of CAD was assessed by Gensini score in AMI and CAD groups. The effects of sleep factors on AMI risk and Gensini score were examined by unconditional logistic regression.

Results

After mutually adjustment for other sleep factors and demographic characteristics, the timing of sleep (24:00 and after) and morning waking (after 7:00) and sleep duration (< 6 h) were associated with increased risk of AMI (OR = 4.005, P < 0.001, OR = 2.544, P = 0.011 and OR = 2.968, P < 0.001, respectively). Lower level of light exposure at night was correlated with reduced risk of AMI (OR = 0.243, P = 0.009). In subgroup analysis by age, both late sleep timing and short sleep duration were associated with increased risk of AMI regardless of age. In subjects with age ≤ 65 years, daytime napping was related to reduced risk of AMI (OR = 0.645, P = 0.046). In subjects with age > 65 years, the frequency of night-time waking (3 times) was associated with increased risk of AMI (OR = 3.467, P = 0.035). Short sleep duration was correlated with increased risk of high Gensini score (OR = 2.374, P < 0.001).

Conclusion

Sleep insufficiency is an important risk factor both for AMI risk and CAD severity. Late sleeping is also associated with increased risk of AMI. In young and middle-aged people, regular naps may have a protective effect.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02251-8.